Amifostine Protects Bone Marrow from Benzene-Induced Hematotoxicity in Mice

Daphnetin exerts an anticancer effect by attenuating the pro-inflammatory cytokines

Leukemia is a malignant tissue-forming disease, which induces the overproduction of large numbers of immature blood cells entering the peripheral blood. It is well documented that inflammation plays a crucial role in the expansion of leukemia. Daphnetin has confirmed anti-inflammatory effects against various diseases. In this experimental study, we evaluated the anti-leukemia and anti-inflammatory effect of daphnetin against benzene-induced leukemia in rats and explored the underlying mechanism. Benzene was used for inducing leukemia in experimental rats. The rats were divided into different groups and the body weight, hematological parameters, bone marrow cells, cytokines, and inflammatory mediators were estimated. Reverse transcription polymerase chain reaction (RT-PCR) was used for estimating the messenger RNA (mRNA) expression of sphingosine-1-phosphate receptor-1. Daphnetin-treated rats showed upregulation of body weight compared to other groups. Moreover, Daphnetin reduced blasts in leukemic rats. It also altered hematological parameters such as red blood cells, white blood cells, lymphocytes, neutrophils, monocytes, eosinophils, monocytes, and basophils, respectively. Daphnetin-treated rats showed a reduction of pro-inflammatory cytokines such as tumor necrosis factor-α, interleukin-1β (IL-1β), IL-2, IL-6, and inflammatory mediators including nuclear factor-κB. RT-PCR showed upregulated mRNA expression of sphingosine-1-phosphate receptor-1 of daphnetin-treated group rats compared to other groups. The current study showed that the anti-inflammatory effect of daphnetin against the benzene-induced leukemia via alteration of cytokines.

Treatment Effect of Low-Intensity Pulsed Ultrasound on Benzene- and Cyclophosphamide-Induced Aplastic Anemia in Rabbits

BACKGROUND

Transplantation and immunosuppressive therapies are the available treatments for aplastic anemia; however, each strategy has its advantages and disadvantages.

OBJECTIVE

The aim of this study was to find a new strategy for aplastic anemia treatment.

DESIGN

This was an experimental and comparative study.

METHODS

The aplastic anemia model was established by injecting rabbits with benzene and cyclophosphamide. The rabbits with aplastic anemia were divided into low-intensity pulsed ultrasound (LIPUS) and control groups. The distal femoral metaphysis of rabbits in the LIPUS group was treated with ultrasound for 30 days (20 min/d), whereas the control group received a sham treatment. Diarrhea, mortality, and blood cell count were evaluated. The levels of forkhead box P3, interleukin 17, interleukin 4, and interferon gamma were measured using an enzyme-linked immunosorbent assay. Bone marrow hyperplasia was observed by hematoxylin-eosin staining and scanning electron microscopy.

RESULTS

The numbers of red blood cells (RBCs), white blood cells (WBCs), and platelets (PLTs) were lower, the amount of hematopoietic tissue was lower, and the amount of adipose tissue was higher in the rabbit aplastic anemia model than in the normal rabbits. The numbers of RBCs, WBCs, and PLTs increased after LIPUS treatment. The interleukin 17 level decreased, whereas the forkhead box P3 level increased. The amount of hematopoietic tissue increased, whereas the amount of adipose tissue decreased.

LIMITATIONS

The number of hematopoietic stem cells could not be evaluated.

CONCLUSIONS

LIPUS improved the hematopoietic microenvironment, accelerated the reconstruction of bone marrow cells, and increased the quantity and quality of RBCs, WBCs, and PLTs in the peripheral blood. Hence, it can serve as a novel treatment strategy for aplastic anemia in the future.

Benzene induces haematotoxicity by promoting deacetylation and autophagy

Chronic exposure to benzene is known to be associated with haematotoxicity and the development of aplastic anaemia and leukaemia. However, the mechanism underlying benzene-induced haematotoxicity, especially at low concentrations of chronic benzene exposure has not been well-elucidated. Here, we found that increased autophagy and decreased acetylation occurred in bone marrow mononuclear cells (BMMNCs) isolated from patients with chronic benzene exposure. We further showed in vitro that benzene metabolite, hydroquinone (HQ) could directly induce autophagy without apoptosis in BMMNCs and CD34⁺ cells. This was mediated by reduction in acetylation of autophagy components through inhibiting the activity of acetyltransferase, p300. Furthermore, elevation of p300 expression by Momordica Antiviral Protein 30 Kd (MAP30) or chloroquine reduced HQ-induced autophagy. We further demonstrated that in vivo, MAP30 and chloroquine reversed benzene-induced autophagy and haematotoxicity in a mouse model. Taken together, these findings highlight increased autophagy as a novel mechanism for benzene-induced haematotoxicity and provide potential strategies to reverse this process for therapeutic benefits.

Examination of the effect of ovarian radiation injury induced by hysterosalpingography on ovarian proliferating cell nuclear antigen and the radioprotective effect of amifostine: an experimental study

Aim

The aim of this study was to examine the effect of amifostine on cellular injury in the ovarian tissue induced by hysterosalpingography (HSG).

Methods

In total, forty 4-month old female Wistar Albino rats were assigned into 8 groups. Each group contained 5 rats. Group 1 (G1): rats were decapitated without any procedure. Group 2 (G2): rats were decapitated after 3 hours of total body irradiation. Group 3 (G3): rats were decapitated 3 hours after HSG procedure. Group 4 (G4): rats were decapitated 3 hours after HSG procedure performed 30 min after receiving amifostine 200 mg/kg intraperitoneally. Group 5 (G5): rats were decapitated after 1 month without any procedure. Group 6 (G6): rats were decapitated after 1 month of total body irradiation. Group 7 (G7): rats were decapitated 1 month after HSG procedure. Group 8 (G8): rats were decapitated 1 month after HSG procedure performed 30 min after receiving amifostine 200 mg/kg intraperitoneally. After rats were decapitated under general anesthesia in all groups, blood samples were obtained and bilateral ovaries were removed. One of the ovaries was placed in 10% formaldehyde solution for histological germinal epithelial degeneration, apoptosis and proliferating cell nuclear antigen scoring. The other ovary and blood sera were stored at −80°C. TNF-α, total antioxidant status, total oxidant status, and malondialdehyde levels were studied in tissue samples and anti-mullerian hormone levels in blood samples.

Results

At the end of the first month, there was significant ovarian germinal epithelium degeneration. Proliferating cell nuclear antigen immunoreactivity was significantly reduced in all other groups when compared with G1 and G5.

Conclusion

In conclusion, amifostine could significantly reduce the ovarian cellular injury induced by HSG.

[Establishment of New Zealand rabbit models of aplastic anemia]

OBJECTIVE

To screen for the optimal dose of benzene and cyclophosphamide using an orthogonal design for establishment of New Zealand rabbit models of aplastic anemia.

METHODS

Following an orthogonal experimental design, the effects of 3 levels of 4 factors, namely the dose of benzene (A), the dose of cyclophosphamide (B), the number of benzene injections (C), and the number of cyclophosphamide injections (D) were tested in the establishment of New Zealand rabbit models of aplastic anemia using a L₉ (3⁴) orthogonal table, and the optimal protocol for the model establishment was selected from the 9 experimental groups. Each rabbit received subcutaneous injection of benzene on the back every other day, followed by daily cyclophosphamide injection via the ear vein for prescribed times. The blood routine was examined every 6 days, and before modeling and at 36 days after modeling, a small sample of the femoral bone was collected for bone marrow histopathological examination.

RESULTS

Comparison of the white blood cell, erythrocyte and platelet counts among the 9 groups showed successful modeling in Groups 4-9, and daily mean reduction rates of the cell counts in Groups 7, 8, and 9 differed significantly from those in the other groups (P<0.05). In Group 7, bone marrow sections showed low myelodysplasia, reduced hematopoietic tissue, reduced or even absence of megakaryocytes, and increased fat cells. Further observation found that the rabbits in Group 7 had sustained bone marrow suppression, consistent with the clinical characteristics of the disease.

CONCLUSION

Stable models of aplastic anemia can be established efficiently in New Zealand rabbits by a combination of 8 subcutaneous injections of benzene at 1.5 mL/kg and 4 intravenous injections of cyclophosphamide at 10 mg/kg.

Histone Deacetylase Inhibitors Trichostatin A and MCP30 Relieve Benzene-Induced Hematotoxicity via Restoring Topoisomerase IIα

Dysfunction of histone acetylation inhibits topoisomerase IIα (Topo IIα), which is implicated in benzene-induced hematotoxicity in patients with chronic benzene exposure. Whether histone deacetylase (HDAC) inhibitors can relieve benzene-induced hematotoxicity remains unclear. Here we showed that hydroquinone, a main metabolite of benzene, increased the HDAC activity, decreased the Topo IIα expression and induced apoptosis in human bone marrow mononuclear cells in vitro, and treatment with two HDAC inhibitors, namely trichostatin A (TSA) or a mixture of ribosome-inactivating proteins MCP30, almost completely reversed these effects. We further established a benzene poisoning murine model by inhaling benzene vapor in a container and found that benzene poisoning decreased the expression and activity of Topo IIα, and impaired acetylation of histone H4 and H3. The analysis of regulatory factors of Topo IIα promoter found that benzene poisoning decreased the mRNA levels of SP1 and C-MYB, and increased the mRNA level of SP3. Both TSA and MCP30 significantly enhanced the acetylation of histone H3 and H4 in Topo IIα promoter and increased the expression and activity of Topo IIα in benzene poisoning mice, which contributed to relieve the symptoms of hematotoxicity. Thus, treatment with HDAC inhibitors represents an attractive approach to reduce benzene-induced hematotoxicity.

Involvement of hypoxia-inducible factor-1 α (HIF-1α) in inhibition of benzene on mouse hematopoietic system

Benzene is an occupational and environmental pollutant that damages the hematopoietic system through oxidant mechanisms. The aims of this study were to assess the role of oxidation in benzene-mediated damage by determination of the levels of reactive oxygen species (ROS) and to evaluate the role of hypoxia-inducible factor-1α (HIF-1α) in this process. C57BL/6 mice were exposed to benzene at varying concentrations of 60, 150, or 300 mg/kg/d for 15 d. Mice in the benzene groups displayed weight loss, and hematologic consequences including decreased red and white blood cell counts, reduced platelet count, diminished hemoglobin content, and lower number of hematopoietic stem cells in bone marrow (BM). There was an elevated proportional neutrophil count and decrease in relative thymus weight. In BM there was a significant increase in ROS levels at 150 mg/kg benzene. However, as a result of diminished cellular viability, ROS levels were not markedly different between the 300-mg/kg benzene dose and the control, as the number of hematopoietic stem cells was reduced. HIF-1α expression and protein levels were decreased in BM cells at all doses of benzene. In conclusion, data indicated that HIF-1α may be involved in benzene-induced inhibition of mouse hematopoiesis and that oxidative stress may play a role in the observed toxicity.

Antiosteoporotic effects of Alpinia officinarum Hance through stimulation of osteoblasts associated with antioxidant effects

BACKGROUND/OBJECTIVE

Alpinia officinarum Hance (AOH) is a traditional herbal medicine specific to south China and serves as a civil medication application of an antioxidant. Growing evidence demonstrates that antioxidants are beneficial for the treatment of osteoporosis. This study was designed to investigate the antiosteoporotic effects of total extracts from AOH in ovariectomised (OVX) rats and the different fractions in AOH on primary osteoblasts activities.

METHODS

The total extract of AOH was extracted by refluxing using 95% ethanol, then the five fractions (F1-F5) were separated from AOH using thin-layer chromatography according to polarity from high to low, and the galangin content was determined using high performance liquid chromatography. In an in vivo study, 36 4-month-old female Sprague-Dawley rats were used as a Sham-operated group, OVX with vehicle (OVX), OVX with epimedium flavonoids (EF, 150 mg/kg/d), and OVX with AOH (AOH, 300 mg/kg/d), respectively. Daily oral administration started on Day 3 after OVX and lasted for 12 weeks. In the in vitro study, primary osteoblasts were incubated with AOH, galangin, and five different fractions (F1-F5) with or without hydrogen peroxide (H2O2), respectively.

RESULTS

Treatment with AOH significantly attenuated osteopenia accompanied by a decreased percentage of osteoclast perimeter and bone formation rate per unit of bone surface, enhanced the bone strength, and prevented the deterioration of trabecular microarchitecture associated with a decrease in biochemical parameters of oxidative stress. Furthermore, treatment with AOH, F3, F4, and galangin increased cell viability, differentiation, and mineralisation in osteoblasts with or without H2O2 and rescued the deleterious effects of H2O2 on cell apoptosis and intracellular reactive oxygen species level. The effects on osteoblast formation were highly aligned with the amounts of flavonoids within AOH.

CONCLUSION

These data demonstrate that ethanol extracts from AOH significantly reverse bone loss, partially by increasing bone formation, and by suppressing bone resorption associated with antioxidant effects, suggesting that AOH can be developed as a promising agent for the prevention and treatment of osteoporosis.

Reduction in radiation-induced lymphocytopenia by famotidine in patients undergoing radiotherapy for prostate cancer

BACKGROUND

Ionizing radiation causes a series of hematological alterations especially profound lymphocytopenia during and after the radiotherapy course. To investigate whether famotidine can reduce hematologic toxicity in patients treated with radiotherapy for prostate cancer.

METHODS

A total of 36 patients undergoing radiotherapy for prostate cancer were randomized to receive either placebo or famotidine tablets. Participants were pretreated with 40 mg of oral famotidine or placebo tablets twice daily, 4 and 3 hr before each radiotherapy fraction. The patients received external-beam radiotherapy up to 70 Gy. Complete blood counts with differential, platelet counts, and hemoglobin levels were obtained at baseline, biweekly during the treatment and once 4 weeks after the end of radiotherapy course. Magnitude of changes from baseline in the hematological parameters was determined and compared using Repeated Measures ANOVA.

RESULTS

Famotidine was well tolerated. A total of 112 blood samples were evaluated. A significant reduction in radiation-induced lymphocytopenia was noted in patients receiving famotidine than in patients receiving placebo (P = 0.006). No significant difference was observed between two groups for the decline in platelets, erythrocytes and leucocytes. For both groups, neutrophil, monocyte, eosinophil, and hemoglobin levels did not change significantly during the treatment.

CONCLUSIONS

Our results indicate that famotidine could result in a significant reduction in radiation-induced lymphocytopenia and may consequently increase radiotherapy efficacy as well as survival times. This radioprotective effect may be chiefly associated with its antioxidant and radical scavenging properties. Further studies are required to confirm these encouraging results.

Aplastic anemia: what have we learned from animal models and from the clinic

Aplastic anemia (AA) is currently perceived as an immune-mediated disease in which aberrant effector cells recognize and destroy primitive marrow elements, resulting in pancytopenia. The immune hypothesis is based on clinical observations of responsiveness of AA to immunomodulatory agents such as anti-thymocyte globulin (ATG) and the requirement of cyclosporine to maintain response; evidence of an immune system in disarray provided by abnormal regulatory, TH1, TH17, and expanded CD8(+) T-cell populations, and animal models of immune-mediated marrow destruction, where many of the observed clinical and in vitro alterations can be confirmed and expanded. Murine models mimicking AA have used exposure to agents that result in marrow destruction through a direct toxic effect, but models that explore antigenic disparities between strains have resulted in immune-mediated destruction of the marrow, more closely modeling human AA. Many experiments in mice have helped confirm and elucidate specific mechanisms of marrow destruction. However, clinical development of regimens in AA has not relied on establishing their success in murine model. Instead, drugs and their combinations investigated in AA were those shown clinically to be active in AA, in other hematologic diseases, or in other specialties such as in rheumatology, and solid and bone marrow transplantation. In this review, the evolution of murine models and their clinical relevance in AA are discussed.

Benzene activates caspase-4 and -12 at the transcription level, without an association with apoptosis, in mouse bone marrow cells lacking the p53 gene

Benzene is a well-known environmental pollutant that can induce hematotoxicity, aplastic anemia, acute myelogenous leukemia, and lymphoma. However, although benzene metabolites are known to induce oxidative stress and disrupt the cell cycle, the mechanism underlying lympho/leukemogenicity is not fully understood. Caspase-4 (alias caspase-11) and -12 are inflammatory caspases implicated in inflammation and endoplasmic reticulum stress-induced apoptosis. The objectives of this study were to investigate the altered expression of caspase-4 and -12 in mouse bone marrow after benzene exposure and to determine whether their alterations are associated with benzene-induced bone marrow toxicity, especially cellular apoptosis. In addition, we evaluated whether the p53 gene is involved in regulating the mechanism, using both wild-type (WT) mice and mice lacking the p53 gene. For this study, 8-week-old C57BL/6 mice [WT and p53 knockout (KO)] were administered a benzene solution (150 mg/kg diluted in corn oil) via oral gavage once daily, 5 days/week, for 1 or 2 weeks. Blood and bone marrow cells were collected and cell counts were measured using a Coulter counter. Total mRNA and protein extracts were prepared from the harvested bone marrow cells. Then qRT-PCR and Western blotting were performed to detect changes in the caspases at the mRNA and protein level, respectively. A DNA fragmentation assay and Annexin-V staining were carried out on the bone marrow cells to detect apoptosis. Results indicated that when compared to the control, leukocyte number and bone marrow cellularity decreased significantly in WT mice. The expression of caspase-4 and -12 mRNA increased significantly after 12 days of benzene treatment in the bone marrow cells of benzene-exposed p53KO mice. However, apoptosis detection assays indicated no evidence of apoptosis in p53KO or WT mice. In addition, no changes of other apoptosis-related caspases, such as caspase-3 and -9, were found in WT or p53KO mice at the level of mRNA and proteins. These results indicated that upregulation of caspase-4 and -12 in mice lacking the p53 gene is not associated with cellular apoptosis. In conclusion, caspase-4 and -12 can be activated by benzene treatment without inducing cell apoptosis in mouse bone marrow, which are partly under the regulation of the p53 gene.